U.S. patent application number 14/765010 was filed with the patent office on 2015-12-24 for flash thermography double wall thickness measurement.
The applicant listed for this patent is UNITED TECHNOLOGIES CORPORATION. Invention is credited to Jesse R. Boyer, Zhong Ouyang, Hector M. Pinero, David A. Raulerson, Kevin D. Smith, Jaimie Taraskevich.
Application Number | 20150369596 14/765010 |
Document ID | / |
Family ID | 51428784 |
Filed Date | 2015-12-24 |
United States Patent
Application |
20150369596 |
Kind Code |
A1 |
Ouyang; Zhong ; et
al. |
December 24, 2015 |
FLASH THERMOGRAPHY DOUBLE WALL THICKNESS MEASUREMENT
Abstract
A method of determining the thickness of an internal wall in a
gas turbine engine component includes the steps of utilizing flash
thermography to measure a complete thickness of a component between
an outer wall and at least one enlarged cooling channel at a
location where an outer cooling channel is positioned between the
outer wall and the at least one enlarged cooling channel and where
at least one member spans the cooling channel, such that the
thickness is through the member which spans the outer cooling
channel. An outer thickness of the component is measured from the
outer wall to an outer wall of the outer cooling channel. A
thickness is determined from an inner wall of the outer cooling
channel to the at least one enlarged cooling channel by subtracting
the measured outer thickness from the complete thickness, and also
subtracting a known thickness of the outer cooling channel.
Inventors: |
Ouyang; Zhong; (Glastonbury,
CT) ; Raulerson; David A.; (Palm Beach Gardens,
FL) ; Smith; Kevin D.; (Glastonbury, CT) ;
Pinero; Hector M.; (Middletown, CT) ; Taraskevich;
Jaimie; (Tolland, CT) ; Boyer; Jesse R.;
(Manchester, CT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
UNITED TECHNOLOGIES CORPORATION |
Hartford |
CT |
US |
|
|
Family ID: |
51428784 |
Appl. No.: |
14/765010 |
Filed: |
February 27, 2014 |
PCT Filed: |
February 27, 2014 |
PCT NO: |
PCT/US2014/018819 |
371 Date: |
July 31, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61771107 |
Mar 1, 2013 |
|
|
|
Current U.S.
Class: |
374/121 |
Current CPC
Class: |
G01B 21/085 20130101;
G01J 5/0896 20130101; G01J 2005/0081 20130101; G01N 25/00 20130101;
G01J 5/0088 20130101 |
International
Class: |
G01B 21/08 20060101
G01B021/08; G01N 25/00 20060101 G01N025/00; G01J 5/00 20060101
G01J005/00 |
Claims
1. A method of determining the thickness of an internal wall in a
gas turbine engine component comprising the steps of: (a) utilizing
flash thermography to measure a complete thickness of a component
between an outer wall and at least one enlarged cooling channel at
a location where an outer cooling channel is positioned between
said outer wall and the at least one enlarged cooling channel and
where at least one member spans said outer cooling channel, such
that said thickness is through said member which spans said outer
cooling channel; and (b) measuring an outer thickness of said
component from said outer wall to an outer wall of said outer
cooling channel, and determining a thickness from an inner wall of
said outer cooling channel to said at least one enlarged cooling
channel by subtracting said measured outer thickness from said
complete thickness, and also subtracting a known thickness of said
outer cooling channel.
2. The method as set forth in claim 1, wherein a high emissivity
outer layer is provided on said outer wall prior to said flash
thermography.
3. The method as set forth in claim 1, wherein said flash
thermography includes directing a flash of light at the outer wall
of said component and then capturing images over time at an
infrared camera to determine a change in heat at said outer wall at
different surface locations.
4. The method as set forth in claim 3, wherein said change in heat
is determined on a pixel by pixel basis.
5. The method as set forth in claim 1, wherein said measured outer
thickness is measured at a second said location generally aligned
on said outer wall of said component, but spaced in a radial
direction from a location at which said member spans said outer
cooling channel, and where there is a space between the inner wall
and outer wall of said outer cooling channel.
6. The method as set forth in claim 1, wherein said measured
complete thickness and measured outer thickness are taken at
locations spaced from each other between a trailing edge and a
leading edge of said component.
7. The method as set forth in claim 1, wherein said component
includes an airfoil with said at least one enlarged cooling channel
and said outer cooling channel.
8. The method as set forth in claim 1, wherein said outer cooling
channel is a microcircuit cooling channel.
9. A method of determining the thickness of an internal wall in a
gas turbine engine airfoil including an outer cooling channel
comprising the steps of: (a) utilizing flash thermography to
measure a complete thickness between an outer wall and at least one
enlarged cooling channel at a location where an outer cooling
channel is positioned between said outer wall and the at least one
enlarged cooling channel and where at least one member spans said
outer cooling channel, such that said thickness is through said
member which spans said outer cooling channel; and (b) measuring an
outer thickness from said outer wall to an outer wall of said outer
cooling channel, and determining a thickness from an inner wall of
said outer cooling channel to said at least one enlarged cooling
channel by subtracting said measured outer thickness from said
complete thickness, and also subtracting a known thickness of said
outer cooling channel.
10. The method as set forth in claim 9, wherein a high emissivity
outer layer is provided on said outer wall prior to said flash
thermography.
11. The method as set forth in claim 9, wherein said flash
thermography includes directing a flash of light at the outer wall
and then capturing images over time at an infrared camera to
determine a change in heat at said outer wall at different surface
locations.
12. The method as set forth in claim 11, wherein said change in
heat is determined on a pixel by pixel basis.
13. The method as set forth in claim 9, wherein said measured outer
thickness is measured at a second said location generally aligned
on said outer wall, but spaced in a radial direction from a
location at which said member spans said outer cooling channel, and
where there is a space between the inner wall and outer wall of
said outer cooling channel.
14. The method as set forth in claim 9, wherein said outer cooling
channel is a microcircuit cooling channel.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to U.S. Provisional
Application No. 61/771107, filed Mar. 1, 2013.
BACKGROUND
[0002] This application relates to a method of determining a
thickness of an inner wall in a gas turbine engine component.
[0003] Gas turbine engines are known and, typically, include a fan
delivering air into a compressor section where it is compressed and
delivered downstream into a combustor section. The air is mixed
with fuel and ignited in the combustor section and products of this
combustion pass downstream over turbine rotors driving them to
rotate. The turbine rotors typically carry blades. Rows of static
vanes are placed intermediate rows of the blades. The blades and
the vanes become quite hot due to the hot products of
combustion.
[0004] Thus, it is known to provide cooling channels within the gas
turbine engine components. The blades and the vanes typically
include an airfoil receiving the cooling channels. Historically,
there were relatively large central cooling channels. A wall
thickness between an outer wall of the airfoil and the channel must
be carefully maintained and designed.
[0005] It was known in the art to provide various inspection means
for measuring a thickness between the outer wall and the cooling
channels in manufactured airfoils to ensure that it meets the
design specifications. One method of measuring the wall thickness
was flash thermography.
[0006] Flash thermography is a known method of measuring thickness
or looking for flaws within a body. Essentially, a flash of light
energy is directed off a component to be inspected. This
dramatically and quickly raises the temperature of the component.
An infrared camera repeatedly captures images of the surface and
can determine changes in the heat at the surface. Modern flash
thermography systems are able to evaluate those changes on a pixel
by pixel basis and, thus, can provide temperature change
information over very precise areas on the surface of the
component.
[0007] Those changes can be translated to a thickness in the
component based upon the material of the component and utilizing
algorithms well known in the art.
[0008] More recently, gas turbine engine components having airfoils
have been provided with so-called cooling channels. The cooling
circuits are precisely made to an exact width and have sometimes
been placed between an outer wall and the relatively larger central
cooling channels.
[0009] Flash thermography is not able to provide accurate
measurements of the distance from an inner wall of the microcircuit
to the enlarged central cooling channel.
SUMMARY
[0010] In a featured embodiment, a method of determining the
thickness of an internal wall in a gas turbine engine component
includes the steps of utilizing flash thermography to measure a
complete thickness of a component between an outer wall and at
least one enlarged cooling channel at a location where an outer
cooling channel is positioned between the outer wall and the at
least one enlarged cooling channel and where at least one member
spans the outer cooling channel, such that the thickness is through
the member which spans the outer cooling channel. An outer
thickness of said component is measured from the outer wall to an
outer wall of the outer cooling channel. A thickness is determined
from an inner wall of the outer cooling channel to the at least one
enlarged cooling channel by subtracting the measured outer
thickness from the complete thickness, and also subtracting a known
thickness of the outer cooling channel.
[0011] In another embodiment according to the previous embodiment,
a high emissivity outer layer is provided on the outer wall prior
to the flash thermography.
[0012] In another embodiment according to any of the previous
embodiments, the flash thermography includes directing a flash of
light at the outer wall of the component and then capturing images
over time at an infrared camera to determine a change in heat at
the outer wall at different surface locations.
[0013] In another embodiment according to any of the previous
embodiments, the change in heat is determined on a pixel by pixel
basis.
[0014] In another embodiment according to any of the previous
embodiments, the measured outer thickness is measured at a second
location generally aligned on the outer wall of the component, but
spaced in a radial direction from a location at which the member
spans the outer cooling channel, and where there is a space between
the inner wall and outer wall of the outer cooling channel.
[0015] In another embodiment according to any of the previous
embodiments, the measured complete thickness and measured outer
thickness are taken at locations spaced from each other between a
trailing edge and a leading edge of the component.
[0016] In another embodiment according to any of the previous
embodiments, the component includes an airfoil with at least one
enlarged cooling channel and the outer cooling channel.
[0017] In another embodiment according to any of the previous
embodiments, the outer cooling channel is a microcircuit cooling
channel.
[0018] In another embodiment according to any of the previous
embodiments, a method of determining the thickness of an internal
wall in a gas turbine engine airfoil including an outer cooling
channel includes the steps of utilizing flash thermography to
measure a complete thickness between an outer wall and at least one
enlarged cooling channel at a location where an outer cooling
channel is positioned between the outer wall and the at least one
enlarged cooling channel and where at least one member spans the
outer cooling channel such that the thickness is through the member
which spans the outer cooling channel. An outer thickness is
measured from the outer wall to an outer wall of the outer cooling
channel. A thickness is determined from an inner wall of the outer
cooling channel to at least one enlarged cooling channel by
subtracting the measured outer thickness from the complete
thickness, and also subtracting a known thickness of the outer
cooling channel.
[0019] In another embodiment according to the previous embodiments,
a high emissivity outer layer is provided on the outer wall prior
to the flash thermography.
[0020] In another embodiment according to any of the previous
embodiments, the flash thermography includes directing a flash of
light at the outer wall and then capturing images over time at an
infrared camera to determine a change in heat at the outer wall at
different surface locations.
[0021] In another embodiment according to any of the previous
embodiments, the change in heat is determined on a pixel by pixel
basis.
[0022] In another embodiment according to any of the previous
embodiments, the measured outer thickness is measured at a second
location generally aligned on the outer wall, but spaced in a
radial direction from a location at which the member spans the
outer cooling channel, and where there is a space between the inner
wall and outer wall of the outer cooling channel.
[0023] In another embodiment according to any of the previous
embodiments, the outer cooling channel is a microcircuit cooling
channel.
[0024] These and other features may be best understood from the
following drawings and specification.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] FIG. 1A shows an airfoil which may be incorporated into a
gas turbine engine.
[0026] FIG. 1B is an enlarged view of a portion of the airfoil.
[0027] FIG. 1C shows a method being performed on the same portion
as shown in FIG. 1B.
[0028] FIG. 2A shows an alternative method.
[0029] FIG. 2B shows a detail of FIG. 2A.
[0030] FIG. 3 is a flow chart.
DETAILED DESCRIPTION
[0031] A component having an airfoil 20 which may be a turbine
blade or vane for use in a gas turbine engine, is illustrated in
FIG. 1A. As shown, the airfoil 20 extends from a leading edge 22 to
a trailing edge 24 and has a body 26 with enlarged central cooling
channels 28, 30 and 32. As can be appreciated, this is a
cross-section through the airfoil 20 and the channels 28, 30 and 32
would be generally closed off at a radially outer end, and there
would be a platform for mounting the blade at a radially inner end.
In the case of a vane, there may be platforms at each of a radially
inner and a radially outer end in some embodiments.
[0032] One side wall 36 of the airfoil 20 is illustrated receiving
a microcircuit cooling channel 34. The microcircuit cooling channel
34 is aligned with the channel 30. In practice, the airfoil 20 may
have microcircuit cooling channels on both sides of the airfoil,
and may even have microcircuit cooling channels associated with
each of the enlarged central cooling channels 28, 30 and 32.
However, for purposes of understanding this invention, we need
consider only one microcircuit cooling channel 34.
[0033] As shown in FIG. 1B, a flash thermography inspection
operation is being utilized on the airfoil 20. As known, a light
pulse from a light source 44 is directed off an outer surface 36 of
the airfoil body 26. A high emissivity paint 40 may be applied to
the outer surface 36 to increase the heat absorption from that
light source 44 into the body 26. The light pulse whose width was
controlled by quench circuit and computer need only last a few
milliseconds.
[0034] As the part cools, an infrared camera 46 captures
information as shown schematically. The camera 46 can evaluate the
heat change on a pixel by pixel basis and, thus, can determine a
thickness T.sub.1 between the outer wall 36 and the cooling channel
28. Any number of known algorithms can be utilized to calculate the
thickness T.sub.1.
[0035] Challenges arise, however, when there are two internal
cavities, such as when a microcircuit cooling channel 34 is aligned
with an enlarged central cooling channel 30. The flash thermography
method can be utilized to determine the thickness between the outer
wall 36 and an outer side 42 of the microcircuit cooling channel
34. This is shown as T.sub.2. However, flash thermography can
provide no information about the thickness T.sub.3 between the
inner wall 43 of the microcircuit cooling channel 34 and the outer
wall of the central cooling channel 30.
[0036] The present invention provides a method of determining the
thickness T.sub.3.
[0037] As shown in FIG. 1C, a thickness T.sub.4 is measured from
the outer wall 36 through any one of a plurality of pedestals or
ribs 136, which extend across the microcircuit cooling channel 34
between the surfaces 42 and 43. Flash thermography is utilized to
determine T.sub.4.
[0038] A thickness T.sub.5, which is the radial thickness of the
microcircuit, is closely controlled and known.
[0039] FIGS. 2A and 2B show an alternative, wherein the thickness
T.sub.2 is measured at a location aligned with the location of the
thickness T.sub.4. As can be appreciated from FIG. 2A, the rib or
pedestal 136 does not extend throughout the entire radial length of
the body 26, but is relatively limited. As shown in FIG. 2B, the
thickness T.sub.2 may be taken radially spaced from the rib 136,
but otherwise at an aligned location. By selecting radially spaced
locations to measure the thicknesses T.sub.2 and T.sub.4, it more
likely that the thickness T.sub.3 will be the same for the two
locations. The selection of the relative locations for the
measurements of T.sub.2 and T.sub.4 may be as shown in FIGS. 1B and
C or as FIG. 2 depending on the overall shape of the airfoil.
[0040] Now, once the thickness of T.sub.2 and T.sub.4 are known,
FIG. 3 shows a method of calculating the thickness T.sub.3. As
shown as step 100, T.sub.2 is measured and then T.sub.4 is measured
at 102. As shown at step 104, T.sub.3 is simply the T.sub.4
measurement minus the sum of T.sub.2 and the known thickness
T.sub.5 of the microcircuit cooling channel 34.
[0041] In this manner a method is provided which accurately
determines the thickness T.sub.3.
[0042] As can be appreciated, the infrared camera 46 may include a
computer, or it may communicate with a computer to provide the
measurements of steps 100, 102 and 104. This is shown schematically
in FIG. 3 by the dotted outline 200, which is representative of a
computer for performing the method. Notably, the computer 200
provides an output 201, which may be a display of the determined
T.sub.3.
[0043] While the method of this disclosure has been disclosed for a
component including a microcircuit cooling channel 34, the
teachings would extend to other outer cooling channels positioned
between an enlarged internal cooling channel and the outer
wall.
[0044] Although an embodiment of this disclosure has been
disclosed, a worker of ordinary skill in this art would recognize
that certain modifications would come within the scope of this
disclosure. For that reason, the following claims should be studied
to determine the true scope and content of this disclosure.
* * * * *